JP2019073588A - Curable composition - Google Patents

Abstract

To provide a curable composition having a high refractive index while maintaining curability as a sealing material.SOLUTION: A curable composition at least contains (A) a compound having a structure to which at least one aromatic hydrocarbon group having a vinyl group is directly bonded, (B) a compound having at least one thiol group, and (C) a polymerization initiator, and has a viscosity of 1-100 mPa s.SELECTED DRAWING: None

Description

The present invention relates to a curable composition useful as a sealing material of an organic electroluminescent device applicable to applications such as display devices and lighting devices.
An object of the present invention is to provide a curable composition having a high refractive index and excellent coating properties and transparency while maintaining the curing performance as a sealing material.

  Various curable materials have been proposed as curable compositions for forming a cured product, for the purpose of protecting an object with the cured product. For example, an organic electroluminescent (EL) device having a laminated structure including an anode, an organic light emitting layer, and a cathode is known as one of the devices for electronic devices that has been developed in recent years.

  However, since the light emitting material contained in the organic light emitting layer is easily deteriorated by moisture and oxygen, it is necessary to seal the organic EL element. Then, in order to protect an organic light emitting layer, element sealing using a curable composition is known (patent document 1). In addition, since the light emission of the organic EL element occurs in the element, various methods are taken for extracting the light, and generally, the refractive index of each layer from the light emitting layer to the outermost layer is adjusted. Has been devised to increase the light extraction efficiency (Patent Document 2).

  In sealing of an organic EL element, in order to reduce damage to the element, a baking-less, solventless hardening composition is desired, and photocurability is considered to be desirable (Patent Document 3). Moreover, the inkjet coating method is spreading from a viewpoint of liquefaction-saving, and a low viscosity hardening composition is desired as inkjet coating aptitude.

However, the cured product described in Patent Document 3 has a problem that it is not suitable for inkjet coating because the viscosity of the photocurable one is high.
As described above, a curable composition having a photocurable property, no solvent, low viscosity, and high refractive index is required as a sealing material for an organic EL element.

JP, 2014-225380, A Patent No. 5395677 Patent 5479248 gazette

  It is an object of the present invention to be solventless, low viscosity, high refractive index, and curable only by light irradiation without heating in order to improve the sealing performance, damage reduction, ink jet coatability and light extraction efficiency of the above-mentioned organic EL element It is an object of the present invention to provide a curable composition.

  The present inventors diligently studied to solve the above problems. As a result, it has been found that the above-mentioned problems can be solved by the curable composition having the following constitution, and the present invention has been completed.

  Furthermore, according to the present invention, it is possible to provide a curable composition which is excellent in the wettability and spreadability on the ink jet application object, and hence the film unevenness is small, and the generation of the outgassing after curing is small. And while maintaining sealing performance, the sealing material which has a refractive index which can improve light extraction efficiency can be obtained. Moreover, it can use suitably also as a material for microlens formation used for a solid-state image sensor etc. using such a characteristic.

(1) a compound having a structure in which one or more aromatic hydrocarbon groups having at least (A) a vinyl group are directly bonded,
(B) a compound having one or more thiol groups, and (C) a polymerization initiator,
Curable composition having a viscosity of 1 to 100 mPa · s.
(2) The curable composition according to the above (1), wherein the aromatic hydrocarbon group having a vinyl group of the compound (A) is a vinylphenyl group.
(3) The curable composition as described in said (1) or (2) whose molecular weight of said (A) compound is 100 or more and 1000 or less.
(4) A cured film having a refractive index of 1.60 or more, which is obtained by curing the curable composition according to any one of (1) to (3).
(5) The curable composition according to any one of (1) to (3), which is used for forming a sealing film of an organic EL element.
(6) An organic EL device containing the sealing film according to (5).

Hereinafter, although an embodiment of the present invention is described in detail, it is not limited to this.
<Curable composition>
The curable composition of the present invention comprises a compound having a structure in which at least (A) an aromatic hydrocarbon group having a vinyl group is directly bonded to one or more, (B) a compound having one or more thiol groups, and A curable composition containing a polymerization initiator and having a viscosity of 1 to 100 mPa · s.
In the present invention, the compound (A) and the compound (B) may be different compounds, and a structure in which at least one aromatic hydrocarbon group having a vinyl group in one molecule is directly bonded to one or more thiols It may be a compound having both of the structure having a group and the compound (A) and the compound (B).

<(A) Compound>
The compound (A) of the present invention is a compound having a structure in which one or more aromatic hydrocarbon groups having a vinyl group in one molecule are directly bonded.
Examples of the aromatic hydrocarbon ring of the present invention include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a chrysene ring, a pyrene ring, a triphenylene ring and the like, with a benzene ring and a naphthalene ring being preferable.

  The vinyl group of the present invention is directly bonded to the aromatic hydrocarbon ring. At least one aromatic hydrocarbon group having a vinyl group is preferably present in one molecule, and preferably two or more.

  Specifically, styrene, divinylbenzene, diisopropenylbenzene, 1-vinylnaphthalene, 2-vinylnaphthalene, 1,4-divinylnaphthalene, 1,5-divinylnaphthalene, 1,6-divinylnaphthalene, 2,6-divinyl Naphthalene, 2,7-divinylnaphthalene, 9-vinyl anthracene, 2-vinyl anthracene, 9-vinyl phenanthrene, 3-vinyl phenanthrene, vinyl triphenylene and the like can be mentioned. Diisopropenylbenzene, 1-vinylnaphthalene, 2-vinylnaphthalene, 1,4-divinylnaphthalene, 1,5-divinylnaphthalene, 1,6-divinylnaphthalene, 2,6-divinylnaphthalene 2,7-divinylnaphthalene is preferred in view of volatility and viscosity.

<(B) Compound>
The compound (B) of the present invention is a compound having one or more thiol groups. It is preferable to have two or more thiol groups. Specifically, (B-1) to (B-17) can be mentioned. Preferably they are (B-2)-(B-16), More preferably, they are (B-7a)-(B-7c).

<Compound Having (A) and (B) in the Same Molecule>
Specifically, (1-1) to (1-4) can be mentioned. However, _{R 1} represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, n represents an integer of 0.

From the viewpoint of film loss due to volatilization at the time of spin coating or inkjet coating, the (A) compound and the (B) compound preferably have a molecular weight of about 100 to 1000, and preferably 135 or more. In particular, the (A) compound is preferably at least 100 and at most 1,000. In the case of the compound which has (A) and (B) in the same molecule, it is preferable that they are 135 or more and 1000 or less.
The ratio of vinyl group to thiol group is 10 to 1000 parts by mole, preferably 50 to 200 parts by mole of thiol per 100 parts by mole of vinyl group. At this ratio, a good cured film can be obtained by the photoene-thiol reaction.

The thiol group does not have to be directly bonded to the aromatic hydrocarbon ring, but at least one is present in one molecule, and preferably two or more.
From the viewpoint of outgassing, the boiling point is 150 ° C. or more, and preferably 200 ° C. or more. The total of the (A) compound and the (B) compound is contained in an amount of 30 to 99% by mass of the curable composition.

  Specific compounds are listed below.

<(C) polymerization initiator>
The polymerization initiator preferably used in the present invention is preferably a photoinitiator, and includes a photo radical initiator.
The (C) polymerization initiator of the present invention is contained in an amount of 1 to 10% by mass of the curable composition.

«Photo radical initiator»
As a photo radical initiator, For example, O-acyl oxime compound, acetophenone compound, biimidazole compound, radiation sensitive cationic polymerization initiator, benzoin compound, benzophenone compound, α-diketone compound, polynuclear quinone compound, xanthone compound, phosphine compound And triazine compounds.

As a specific example of the said O-acyl oxime compound, 1- [9-ethyl- 6- (2-methyl benzoyl) -9. H. -Carbazol-3-yl] -ethan-1-one oxime-O-acetate, ethanone-1- [9-ethyl-6- (2-methyl-4-tetrahydrofuranyl methoxy benzoyl) -9. H. -Carbazol-3-yl] -1- (O-acetyloxime) or ethanone-1- [9-ethyl-6- {2-methyl-4- (2,2-dimethyl-1,3-dioxolanyl) methoxybenzoyl] } -9. H. -Carbazol-3-yl] -1- (O-acetyloxime) can be mentioned as a preferred one.
These O-acyl oxime compounds can be used alone or in combination of two or more.

As said acetophenone compound, an alpha-amino ketone compound, an alpha-hydroxy ketone compound, and other acetophenone compounds can be mentioned, for example.
As specific examples of these, as an α-amino ketone compound, for example, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 2-dimethylamino-2- (4-methylbenzyl) )-1-(4-morpholin-4-yl-phenyl) -butan-l-one, 2-methyl-l- (4-methylthiophenyl) -2-morpholinopropan-l-one and the like;
As the α-hydroxy ketone compound, an α-amino ketone compound is preferable, and in particular, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one or 2-dimethylamino-2- (4-methyl) Benzyl) -1- (4-morpholin-4-yl-phenyl) -butan-1-one is preferred.

  Specific examples of the above biimidazole compounds include 2,2′-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole and 2,2′-bis 2,4-Dichlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole or 2,2'-bis (2,4,6-trichlorophenyl) -4,4', 5,5'-tetraphenyl-1,2'-biimidazole is preferred, and in particular 2,2'-bis (2-chlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole. Imidazole is preferred.

<Other additive materials>
The curable composition of the present invention may optionally contain a sensitizer, a polymerization inhibitor, an antioxidant, a surfactant and the like. Although a solvent can be used if necessary, it can be made a curable composition without using it.

[Antioxidant]
The antioxidant is a component capable of decomposing a radical generated by exposure or heating or a peroxide generated by oxidation to prevent the cleavage of the bond of the polymer molecule. As a result, the resulting cured film is prevented from oxidative degradation with time, and, for example, the decrease in luminance of the cured film can be suppressed.

  Specific examples of the antioxidant include hindered phenol type, hindered amine type, phosphorus type, thiol type, benzotriazole type, benzophenone type, hydroxylamine type, salicylic acid ester type, and triazine type compounds. UV absorbers, antioxidants and the like can be used. The antioxidant used in the present embodiment is preferably one containing no halogen atom.

  Among these antioxidants, preferred are hindered phenol-based antioxidants, hindered amine-based antioxidants, phosphorus-based antioxidants or thiol-based antioxidants from the viewpoint of achieving both the transmittance and sensitivity of the coating film. Agents. Also, more preferably, hindered phenol-based antioxidants and thiol-based antioxidants.

  Examples of hindered phenol-based antioxidants include 2,4-bis [(laurylthio) methyl] -o-cresol, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl), 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl), 2,4-bis (n-octylthio) -6- (4-hydroxy-3,5-di-) tert-Butylanilino) -1,3,5-triazine, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,6-di-tert-butyl-4-nonylphenol 2,2'-Isobutylidenebis (4,6-dimethyl-phenol), 4,4'-butylidenebis (2-tert-butyl-5-methylpheno) ), 2,2'-thio-bis (6-tert-butyl-4-methylphenol), 2,5-di-tert-amyl-hydroquinone, 2,2'-thiodiethylbis (3,5-di- tert-Butyl-4-hydroxyphenyl) -propionate, 1,1,3-tris- (2'-methyl-4'-hydroxy-5'-tert-butylphenyl) -butane, 2,2'-methylenebis (6 -(1-methyl-cyclohexyl) -p-cresol), 2,4-dimethyl-6- (1-methyl-cyclohexyl) -phenol, N, N-hexamethylene bis (3,5-di-tert-butyl-) 4-hydroxy-hydrocinnamamide) etc. are mentioned. In addition, compounds of oligomer type and polymer type having a hindered phenol structure can also be used.

  As the hindered amine antioxidant, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (N-methyl-2,2,6,6-tetramethyl-4-piperidyl) sebacate, N, N'-bis (2,2,6,6-tetramethyl-4-piperidyl) -1,6-hexamethylenediamine, 2-methyl-2- (2,2,6,6-tetramethyl-4) -Piperidyl) amino-N- (2,2,6,6-tetramethyl-4-piperidyl) propionamide, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) (1,2,3, 4-butane tetracarboxylate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl} {(2,2,6,6 -Tetramethyl-4-piperidi Imino} hexamethyl {(2,2,6,6-tetramethyl-4-piperidyl) imino}], poly [(6-morpholino-1,3,5-triazine-2,4-diyl) {(2, 2,6,6-Tetramethyl-4-piperidyl) imino} hexamethine {(2,2,6,6-tetramethyl-4-piperidyl) imino}], dimethyl succinate and 1- (2-hydroxyethyl)- Polycondensate with 4-hydroxy-2,2,6,6-tetramethylpiperidine, N, N'-4,7-tetrakis [4,6-bis {N-butyl-N- (1,2,2 , 6,6-Pentamethyl-4-piperidyl) amino} -1,3,5-triazin-2-yl] -4,7-diazadecane-1,10-diamine, etc. Other oligomeric types having a hindered amine structure as well as Rimmer type compounds may also be used.

  As a phosphorus antioxidant, tris (isodecyl) phosphite, tris (tridecyl) phosphite, phenyl isooctyl phosphite, phenyl isodecyl phosphite, phenyl di (tridecyl) phosphite, diphenyl isooctyl phosphite, diphenyl isodecyl Phosphite, diphenyl tridecyl phosphite, triphenyl phosphite, tris (nonylphenyl) phosphite, 4,4 'isopropylidene diphenol alkyl phosphite, tris nonyl phenyl phosphite, tris dinonyl phenyl phosphite, tris (2 , 4-Di-tert-butylphenyl) phosphite, tris (biphenyl) phosphite, distearyl pentaerythritol diphosphite Di (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, phenyl bisphenol A pentaerythritol diphosphite, tetratridecyl-4,4'-butylidene bis ( 3-Methyl-6-tert-butylphenol) diphosphite, hexatridecyl-1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane triphosphite, 3,5- Di-tert-butyl-4-hydroxybenzyl phosphite diethyl ester, sodium bis (4-tert-butylphenyl) phosphite, sodium-2,2-methylene bis (4,6-di-tert-butylphenyl) phosphite , , 1,3-bis (di-phenoxy phosphine sulfonyl b carboxymethyl) - benzene, phosphorous acid ethyl bis (2,4-di -tert- butyl-6-methylphenyl), and the like. In addition, oligomer type and polymer type compounds having a phosphite structure can also be used.

  Examples of thiol-based antioxidants include 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis [(octylthio) methyl]- o-cresol, 2,4-bis [(laurylthio) methyl] -o-cresol, etc. may be mentioned. In addition, oligomer type and polymer type compounds having a thioether structure can also be used.

  As the benzotriazole-based antioxidant, compounds of oligomer type and polymer type having a benzotriazole structure can be used.

  Specific examples of benzophenone-based antioxidants include 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, and 2-hydroxybenzophenone. Hydroxy-4-octadecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2- And hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone and the like. In addition, oligomer type and polymer type compounds having a benzophenone structure can also be used.

  As a triazine type antioxidant, a 2, 4- bis (allyl) 6- (2-hydroxyphenyl) 1, 3, 5- triazine etc. are mentioned. In addition, oligomer type and polymer type compounds having a triazine structure can also be used.

  Examples of the salicylate-based antioxidant include phenyl salicylate, p-octylphenyl salicylate, p-tert-butylphenyl salicylate and the like. In addition, compounds of oligomer type and polymer type having a salicylate structure can also be used.

  As a minimum of content of antioxidant with respect to 100 mass parts of a sum of (A) compound and (B) compound component, 0.01 mass part is preferable, and 0.1 mass part is more preferable. As a maximum of content of the above-mentioned antioxidant, 10 mass parts is preferred, 8 mass parts is more preferred, and 7 mass parts is still more preferred. By making content of antioxidant into the said range, the time-dependent oxidative degradation of the cured film obtained etc. can be suppressed effectively. In addition, when using 2 or more types of antioxidant, the said content is a total amount.

[Surfactant]
The surfactant that can be contained in the curable composition of the present embodiment can be added to improve the coating properties of the curable composition, to reduce coating unevenness, and to improve the developability of the irradiated part. Examples of preferred surfactants include fluorosurfactants and silicone surfactants.

  As a fluorine-based surfactant, for example, 1,1,2,2-tetrafluorooctyl (1,1,2,2-tetrafluoropropyl) ether, 1,1,2,2-tetrafluorooctylhexyl ether, octal Ethylene glycol di (1,1,2,2-tetrafluorobutyl) ether, hexaethylene glycol (1,1,2,2,3,3-hexafluoropentyl) ether, octapropylene glycol di (1,1,2 Fluoroethers such as 2-, 2-tetrafluorobutyl) ether, hexapropylene glycol di (1,1,2,2,3,3-hexafluoropentyl) ether; sodium perfluorododecyl sulfonate; 2,8,8,9,9,10,10-decafluorododecane, 1,1,2,2,3,3-hexa Fluoroalkanes such as fluorodecane; sodium fluoroalkyl benzene sulfonate; fluoro alkyl oxy ethylene ethers; fluoro alkyl ammonium iodides; fluoro alkyl polyoxyethylene ethers; perfluoro alkyl polyoxyethanols; perfluoro alkyl alkoxylates And fluorinated alkyl esters etc. can be mentioned.

As commercially available products of these fluorine-based surfactants, F-Top (registered trademark) EF 301, 303, 352 (manufactured by Shin-Akita Kasei Co., Ltd.), Megafuck (registered trademark) F 171, 172, 173 (DIC Corporation) Florard FC 430, 431 (Sumitomo 3M Co., Ltd.), Asahi Guard AG (registered trademark) 710 (Asahi Glass Co., Ltd.), Surflon (registered trademark) S-382, SC-101, 102, 103, 104 105, 106 (manufactured by AGC Seimi Chemical Co., Ltd.), FTX-218 (manufactured by Neos Co., Ltd.), and the like.
Examples of silicone surfactants are commercially available trade names: SH200-100cs, SH28PA, SH30PA, ST89PA, SH190, SH 8400 FLUID (manufactured by Toray Dow Corning Silicone Co., Ltd.), organosiloxane polymer KP341 (Shin-Etsu Chemical Co., Ltd. product) etc. are mentioned.

  When a surfactant is used as another optional component, its content is preferably 0.01 parts by mass to 10 parts by mass, more preferably 0.05 parts by mass to 100 parts by mass of component (A). It is a mass part. By making the usage-amount of surfactant 0.01 mass part-10 mass parts, the coating property of the curable composition of this embodiment can be optimized.

[Phosphate ester compound]
As a phosphoric acid ester compound, a reaction product of a 6-hexanolide addition polymer of 2-hydroxyethyl methacrylate and phosphoric anhydride ("KAYAMER PM-21" manufactured by Nippon Kayaku Co., Ltd.), alkyl (C12, C14, C16, C18) Acid Phosphate ("JB-512" manufactured by Johoku Chemical Co., Ltd., etc.) Such a phosphoric acid ester compound is preferably 0.01 parts by mass to 10 parts by mass with respect to 100 parts by mass of the component (A). More preferably, it is 0.05 parts by mass to 5 parts by mass Curing obtained from the curable composition of the present embodiment by setting the amount of use of the phosphoric acid ester compound to 0.01 parts by mass to 10 parts by mass The adhesion of the film to the substrate can be improved.

[Adhesive agent]
The adhesion aiding agent can be used for the purpose of further improving the adhesion between the insulating film obtained from the curable composition of the present embodiment and a layer, a substrate or the like disposed therebelow. As the adhesion assistant, functional silane coupling agents having reactive functional groups such as carboxyl group, methacryloyl group, vinyl group, isocyanate group, oxiranyl group are preferably used, and examples thereof include trimethoxysilylbenzoic acid and γ-methacrylic acid. Roxypropyltrimethoxysilane, vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, etc. Can be mentioned.
[Organic solvent]
An organic solvent can be used as needed. The organic solvents can be used alone or in combination of two or more.

As an organic solvent which can be used for the curable composition of this embodiment, while melt | dissolving or disperse | distributing other containing components, the thing which does not react with other containing components can be mentioned.
For example, alcohols such as methanol, ethanol, isopropanol, butanol and octanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether acetate, propylene Esters such as glycol monoethyl ether acetate and methyl 3-methoxy propionate; polyoxyethylene lauryl ether, ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, ethers such as propylene glycol monomethyl ether and diethylene glycol methyl ethyl ether; benzene, Aromatic hydrocarbons such as toluene and xylene; Chill acetamide, etc. amides such as N- methylpyrrolidone.

<Viscosity>
The cured material of the present invention is characterized by having a viscosity of 1 to 100 mPa · s. The viscosity is a value measured at 25 ° C. using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.) in accordance with JIS K2283. By setting it as this viscosity, a curable composition will have wettability suitable for a to-be-hardened | cured material (organic EL element), and sealing property can be ensured.
The viscosity can be adjusted by the molecular weight of the (A) compound and the (B) compound contained in the curable composition and the addition amount ratio, and it is particularly preferable to adjust by the molecular weight of the (A) compound. Moreover, this viscosity range is preferable in that it is also a range in which the increase in viscosity with time does not easily occur.

  The method of forming a cured film of the present embodiment is formed by the following steps.

[Step (1)]
At a process (1), the solution of the said curable composition is apply | coated to a substrate surface, and a coating film is formed by prebaking as needed. Examples of the substrate used in the step (1) include a glass substrate, a silicon wafer, a plastic substrate, and a substrate having various inorganic films such as silicon nitride formed on the surface thereof. As a plastic substrate, for example, a substrate mainly composed of a plastic such as polyethylene terephthalate (PET), polybutylene terephthalate, polyether sulfone, polycarbonate, polyimide and the like can be mentioned.

As a method of applying the curable composition, an appropriate method such as a spray method, a roll coating method, a spin coating method (spin coating method), a slit die coating method, a bar coating method, an inkjet method can be adopted. . Among these coating methods, spin coating and inkjet coating are preferable. The conditions for pre-baking may vary depending on the type, content, etc. of the components of the curable composition, but can be, for example, about 60 seconds to 100 degrees Celsius for about 30 seconds to about 10 minutes. The average film thickness of the coating film is preferably 0.1 μm as the lower limit after prebaking. Moreover, as this upper limit, 15 micrometers is preferable, 10 micrometers is more preferable, and 8 micrometers is more preferable.

[Step (2)]
In the step (2), the coating film formed in the step (1) is irradiated with radiation through a mask having a predetermined pattern. Examples of radiation at this time include ultraviolet light, far ultraviolet light, X-rays, charged particle beams and the like.

The exposure wavelength is preferably 300 to 450 nm. A high pressure mercury lamp or an LED can be used as a light source. The exposure amount, for example, 100 J / ^{m 2} or more 100,000J / ^{m 2} or less. Moreover, you may form a pattern by the imprint method as needed.

[Step (3)]
If necessary, the coating may be cured by heating and baking (post-baking). Moreover, as a minimum of the calcination temperature in a process (3), 80 degreeC is preferable. On the other hand, as this upper limit, 250 ° C is preferred. The firing time varies depending on the type of the heating device, but is, for example, 5 minutes or more and 40 minutes or less when heat treatment is performed on a hot plate, and 30 minutes or more and 80 minutes or less when heat treatment is performed in an oven. be able to.

According to the manufacturing method, a cured film can be formed by exposure and heating utilizing the radiation sensitivity of the curable composition.

<Cured film>
The cured product obtained by curing the curable composition of the present invention has a refractive index of 1.60 or more, preferably 1.65 or more. A cured product of high refractive index can be designed by using a weight element such as a sulfur atom or by increasing the content of condensed hydrocarbon rings. The cured film of the present invention can be used for sealing a liquid crystal display element or an organic EL element, a microlens, an antireflective film, a diffraction grating of an AR element, or the like.

The structural identification of the compound is performed using ¹ H-NMR measurement (manufactured by Bruker, model AVANCE 500), and the measurement of molecular weight is performed using a liquid chromatograph mass spectrometer (LC-MS, manufactured by Shimadzu Corporation, LCMS-8045), It confirmed that the target compound was obtained.
Synthesis Example 1
<Synthesis of Compound (1-1)>
It synthesize | combined according to Reactive & Functional Polymers 73 (2013) 624-633. The molecular weight of (1-1) is 150.24.

Synthesis Example 2
<Synthesis of Compound (1-2)>
Thermometer, 500 mL three-necked flask equipped with a nitrogen inlet tube (1-1) 15.2 g, 15% aqueous sodium hydroxide solution, 35.1 g of propylene sulfide, 200 mL of toluene, 0.02 g of 4-methoxyphenol and benzyltrimethylammonium 0.1 g of chloride was charged and stirred at room temperature for 12 hours. After completion of the reaction, the reaction solution was ice-cooled to 5 ° C. or less, concentrated hydrochloric acid was added to adjust to pH 1, the aqueous layer was removed by a separatory funnel, and after washing three times with water, it was dried with magnesium sulfate. Subsequently, silica column purification (developing solvent: hexane) was carried out, followed by concentration and drying to obtain 15.7 g of (1-2). The molecular weight of (1-2) is 224.39.

Synthesis Example 3
<Synthesis of Compound (1-3)>
The compound tetramercapto compound (1-3B) was synthesized according to Example 1 of Patent No. 3444682. The molecular weight of (1-3B) is 366.74. Subsequently, 9.17 g (0025 mol) of (1-3B), 200 mL of ethanol, 0.02 g of 4-methoxyphenol and 10.1 g of triethylamine were added to a 500 mL three-necked flask equipped with a thermometer and a nitrogen inlet tube. Next, 7.78 g (0.051 mol) of vinylbenzyl chloride was added, and the mixture was stirred at room temperature overnight. After completion of the reaction, the solution was concentrated by filtration, concentrated, and 300 mL of methylene chloride was added, followed by washing with water three times. Next, the organic layer was concentrated, 300 mL of hexane was added, and the supernatant was removed to obtain an oily substance. This operation was repeated, and the oily substance was vacuum-dried to obtain 10.48 g of (1-3: 2-substituted mercapto group). The modification rate determined by proton NMR was 50 mol%. The molecular weight of (1-3) is 599.06.

[Examples 1 to 8, Comparative Examples 1 to 6]
<(1) Preparation of Curable Composition>
After adjustment with the composition shown in Table 1, filtration is performed using a 0.2 μm filter to obtain curable compositions (J-1) to (J-8) and (RJ-1) to (RJ-3). The The materials shown in Table 1 are as shown below.
As Comparative Example 4, the composition described in Example 1 of Japanese Patent No. 5479248 was produced.
The viscosity was measured at 25 ° C. of the curable composition obtained in Examples and Comparative Examples using an E-type viscometer (“TVE22L” manufactured by Toki Sangyo Co., Ltd.) in accordance with JIS K2283. .

(C) Component (C-1): DAROCUR TPO (manufactured by BASF Corp.)
(C-2): Irg. OXE-01 (manufactured by BASF Corporation)

(B) Component VNA: 1-vinyl naphthalene DVNA: 1, 5-divinyl naphthalene DVB: divinyl benzene m, p mixture

The following surfactant S-1 was added at 1% by mass with respect to the total amount of the compound (A) and the compound (C). In Example 9 only, the surface activity was removed from the composition of Example 2.
(S-1): SH 190 (made by Toray Dow Corning Co., Ltd.)

<Evaluation of curable composition>
The following evaluation was performed about the above curable composition. The results are shown in Table 2. In addition, unless otherwise noted, the measurement was performed under an atmosphere of 25 ° C. and 55% RH.

«Photo-curing property»
The number of rotations of the spin coater was adjusted and coated on a 4-inch silicon wafer so that the film thickness was 5 μm. The coating film was irradiated with ultraviolet rays of the following exposure dose to observe the presence or absence of tackiness of the cured film obtained. The exposure amount is 365 nm equivalent.
AA: 1 J / cm ² exposure not tackiness AB: ² J / cm ² exposure no tack BB: ² J / cm ² exposure slightly tackiness CC: ² J / cm ² exposure liquid

«Refractive index»
The cured film ( ² J / cm ² exposure) was measured by a prism coupler method using Model 201 (manufactured by Metricon).

«Preservation stability»
The cured composition was stored in a constant temperature bath at 40 ° C. for 3 days, and the viscosity change rate was evaluated.
(Viscosity change rate) = ((viscosity after storage)-(initial viscosity)) / (initial viscosity) x 100 (%)
Viscosity change rate AA: less than 5% AB: 5 to 10%
BB: 10 to 20%
CC: 20% or more or gelation

«Evaluation of discharge stability»
From the inkjet head of the piezo-type inkjet printer with an ultraviolet irradiation device, a discharge test of the curable compositions 1 to 16 was performed, and the following judgment criteria evaluated.
AA: The curable composition can be discharged from the head at room temperature (20 to 25 ° C.),
Ink jet discharge was possible from all the nozzles visually.
BB: The curable composition can be discharged from the head by heating at 40 to 60 ° C.
Ink jet discharge was possible from all the nozzles visually.
CC: It was impossible to discharge the curable composition from the head at the initial stage of discharge.

«Evaluation of coating film unevenness»
On an evaluation substrate in which SiNx is formed in a film thickness of 100 nm on a glass substrate, the curable compositions 1 to 16 are jetted out from the ink jet head of a piezoelectric inkjet printer at a pitch of 50 μm × 50 μm. A coated film was produced. After 5 minutes, the coating film was cured by irradiating an exposure dose of 1000 mJ / cm ² using the 395 nm LED lamp. At that time, the voltage applied to the ink jet head was changed so that the thickness of the cured film was 10 μm or 5 μm, and the amount of one ink dot ejected was adjusted. The resulting cured film was evaluated based on the following criteria.
AA (excellent): No coating film unevenness is observed visually.
BB (good): Coating film unevenness due to partial change in film thickness is visually observed.
CC (improper): The unapplied part is observed visually.

  From the above results, a curable composition containing a compound having at least one vinyl group directly bonded to an aromatic hydrocarbon ring and at least one thiol group in the same molecule exhibits good photocurability and is highly effective. It is possible to obtain refractive coatings and, furthermore, to apply without solvents.

<Evaluation of sample of organic EL element>
«Fabrication of organic EL device»
A 3 μm-thick planarizing layer having a glass substrate (“OA-10” manufactured by Nippon Electric Glass Co., Ltd.) in which ITO transparent electrodes are formed in an array and a contact hole in which only a part of the ITO transparent electrode is exposed. A plurality of array substrates were prepared.

  An Al film with a thickness of 100 nm was formed on the planarized layer by DC sputtering using an Al target. An ITO film having a thickness of 20 nm was formed on an Al film by DC magnetron reactive sputtering using an ITO target. Thus, the base material in which the anode layer which consists of Al film and ITO film was formed was used.

  A coating is formed on the anode layer using a resist material ("Optomer NN 803" manufactured by JSR), and a series of treatments including i-ray (wavelength 365 nm) irradiation, development, washing with flowing water, air drying and heat treatment are performed. A pixel defining layer having a part of the opening as an opening area was formed.

  The base on which the anode and the pixel defining layer are formed is moved to a vacuum deposition chamber, the deposition chamber is evacuated to 1E-4 Pa, and then holes are formed on the substrate using a deposition mask of a predetermined pattern. An injection-processable molybdenum oxide (MoOx) was deposited by resistance heating deposition under the conditions of a deposition rate of 0.004 to 0.005 nm / sec to form a hole injection layer with a thickness of 1 nm.

  4,4′-Bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD) having hole transportability is formed on the hole injection layer using a deposition mask of a predetermined pattern. A film was formed by resistance heating evaporation under the same exhaust conditions as the hole injection layer to form a hole transport layer having a thickness of 35 nm. The deposition rate was 0.2 to 0.3 nm / sec.

  On the hole transport layer, tris (8-quinolinolato) aluminum which is an alkylate complex as a green light emitting material using a deposition mask of a predetermined pattern by the resistance heating deposition method, and the same film forming conditions as the hole transport layer The light emitting layer was formed to a thickness of 35 nm. The deposition rate was 0.5 nm / sec or less.

Lithium fluoride was deposited on the light emitting layer by resistance heating evaporation under the same exhaust conditions as the hole injecting layer to form an electron injecting layer having a thickness of 0.8 nm. The deposition rate was 0.004 nm / sec or less.
Subsequently, magnesium and Ag were simultaneously formed on the electron injection layer by resistance heating evaporation under the same exhaust conditions as the hole injection layer to form a first cathode layer having a thickness of 5 nm. The deposition rate was 0.5 nm / sec or less.

Subsequently, the substrate was transferred to another film forming chamber (sputtering chamber), and a 100 nm-thick second cathode layer was formed on the first cathode layer by an RF sputtering method using an ITO target.
The organic EL element for evaluation was obtained as mentioned above.

«Thin film sealing of organic EL element»
The thin film sealing layer was formed with the following procedures with respect to the obtained organic EL element. The organic EL element was transferred to a film forming chamber (sputtering chamber), and an inorganic sealing layer (SiNx film) with a film thickness of 100 nm was formed on the cathode layer by RF sputtering using a SiNx target. Subsequently, the organic EL element is transferred into a N ₂ -substituted glove box, and the curable compositions 1 to 16 are discharged in a predetermined pattern by a piezo inkjet printer, and then UniJet E110 ZHD 395 nm LED manufactured by Ushio Inc. The film was irradiated with an exposure amount of 1000 mJ / cm ² using a lamp to cure the formed curable composition, thereby forming an organic sealing layer having a film thickness of 10 μm.

  The organic EL element was transferred to a film forming chamber (sputtering chamber), and an inorganic sealing layer (SiN x film) with a film thickness of 100 nm was formed on the organic sealing layer by RF sputtering using a SiN x target. An organic EL device was obtained as described above.

«Reliability of Organic EL Device»
About each organic EL device obtained above, after storing for 100 h under 85 ° C. 85% RH wet heat conditions, forward current was applied at 10 mA / cm ² , and a light emitting appearance (dark spot) was observed. It evaluated based on the following standard.
A (excellent): Dark spots are not observed.
C (not good): One or more dark spots are observed.

«Light extraction evaluation»
The organic EL device sample is lit under constant current conditions of room temperature (25 ° C., 2.5 mA / cm ² ), and the light emission luminance (L) [cd / m ² ] immediately after the start of lighting is measured to obtain an external device. The efficiency was evaluated. Here, the measurement of light emission luminance was performed using a spectral radiance meter (SR-3AR manufactured by TOPCON), and the external extraction efficiency was evaluated. The results are shown in relative intensity with the luminance of Comparative Example 4 being 100.

«Evaluation rank of light extraction»
A: relative strength is greater than 103 and not greater than 110 B: relative intensity is greater than 100 and not greater than 103 C: relative intensity is not greater than 100

  As described above, it is clear that the curable composition of the present invention contributes not only to the sealing property but also to the light extraction efficiency.

Claims (6)

A compound having a structure in which one or more aromatic hydrocarbon groups having at least (A) a vinyl group are directly bonded,
(B) a compound having one or more thiol groups, and (C) a polymerization initiator,
Curable composition having a viscosity of 1 to 100 mPa · s. The curable composition according to claim 1, wherein the aromatic hydrocarbon group having a vinyl group of the compound (A) is a vinylphenyl group. The curable composition according to claim 1 or 2, wherein the molecular weight of the compound (A) is 100 or more and 1000 or less.   A cured film having a refractive index of 1.60 or more, obtained by curing the curable composition according to any one of claims 1 to 3.   The curable composition according to any one of claims 1 to 3, which is used for forming a sealing film of an organic EL element.   The organic EL element containing the sealing film of the said Claim 5.